This application is related to the prior copending application, Ser. No. 06/108,322, still pending, filed Dec. 28, 1979, by the same inventor. Such prior application is incorporated herein by reference in its entirety.
The invention relates to internal combustion engines with reciprocating or rotating movement of pistons and a divided combustion space, and particularly to a method of preparation of a combustible mixture for such engines and to an apparatus for practicing this method.
Engines with a divided combustion space, wherein in addition to a main combustion space a subsidiary combustion space connected therewith is provided, are known. In such engines a main suction channel controlled by a main suction valve terminates into the main combustion space, from which a discharge channel, controlled by a discharge valve, branches. A subsidiary suction channel controlled by a subsidiary suction valve terminates into the subsidiary combustion chamber, the subsidiary chamber being connected with the main combustion chamber by a flash-over channel. A spark plug or some other means for igniting the combustible mixture is disposed in the subsidiary combustion chamber. In such priors engines, poor or lean combustible mixture is supplied to the main combustion chamber and an easily ignitable richer combustible mixture is supplied to the subsidiary combustion chamber. The spark plug ignites the combustible mixture in the subsidiary chamber when the piston associated with such chambers is in the neighborhood of the upper dead end of its compression stroke. The hot gases flash-over from the subsidiary combustion chamber via a flash-over channel into the main combustions chamber and ignite the poor or lean combustible mixture therein.
It is also known that for the correct operation of the above-described method two combustible mixtures with different air-fuel mixing ratios have to be provided, a poor mixture for the main combustion chamber and a rich one for the subsidiary combustion chamber. For the preparation of both kinds of combustible mixtures known designs of similar engines use two separate devices, either two separate carburetors, the control of which is accomplished, for instance, according to U.S. Pat. No. 1,568,638; 2,121,920; 3,092,088; 3,230,939; and 3,880,942, or according to German Pat. No. 2,259,286 and others, or by a combination of a carburetor and an injection device, used for instance in Honda and Volkswagen engines. A drawback of these known arrangements is the requirement following from the design of the use of two of either the same or different devices, and also their dependent control requiring substantially complicated mechanical or other devices.
It is an object of this invention to provide a method of preparation of a combustible mixture of fuels of different air-fuel mixing ratios, and an arrangement for practicing this method, which are simple, reliable and permit a simple control of the mixing ratios of both kinds of combustible mixtures and which eliminate the drawbacks of known arrangements.
The method of preparation of a combustible mixture with different mixing ratios for the main and subsidiary combustion chamber for internal combustion engines with a divided combustion space according to this invention has been solved by forming the combustible mixtures for both combustion chambers from a single fuel jet which is injected into the main air stream sucked into the main combustion chamber, a part of the fuel being separated from the fuel jet by a subsidiary air stream which is sucked into the subsidiary chamber.
The combustible mixture for the subsidiary combustion chamber according to this invention is furthermore adjusted by a supply of additional air which is advantageously taken from the main stream of sucked-in air. The subsidiary stream of sucked-in air can be taken from the main stream of sucked-in air. For carrying out the method according to this invention an arrangement is provided wherein part of the fuel is sucked into the subsidiary chamber and is furthermore adjusted by the supply of additional air thereto. For this purpose, a stub nipple encompassing the fuel jet is open into the main suction channel, to the main suction conduit, or to the mixing chamber of suction conduits.
It is advantageous to connect the sucking-off chamber with the main suction conduit by a channel for additional air, or to connect it both with the main suction channel and with the main suction conduit, by an annular passage around said stub nipple. The channel for additional air can be connected with the main suction conduit by an opening into which a conical end of a regulating screw protrudes, or it can be connected by an air chamber with the suction tract of the engine, whereby the throttling cone of the regulator of additional air engages into the air chamber.
An air chamber for additional air can be provided in the channel for additional air.
A throttline flap may be provided in the mains suction conduit upstream of the collecting conduit of the main suction conduit.
A throttling glap can be furthermore provided in the main suction conduit upstream of the mixing chamber.
The solution according to this invention provides for an engine with a divided combustion space the advantage of a perfectly prepared combustible mixture with two mixing ratios by the use of a single injection device of any system, for instance with low, medium or high pressure, with continuous or intermittent ejection.
The main advantage of this solution over known arrangements is mainly the more perfect maintenance of the same mixing ratio of the combustible mixture and its distribution to individual cylinders, enabling the achievement for an equal mixing ratio of the combustible mixture lower values of the content of harmful substances particularly of nitrogen oxide in the engine exhaust gases, and providing the possibility to achieve a higher specific output with a simple design without the requirement of extraordinary and costly arrangements of the combustion system.